H(2)S functions as a nociceptive messenger through transient receptor potential ankyrin 1 (TRPA1) activation

Hydrogen sulfide (H(2)S), an endogenous gasotransmitter, modulates various biological functions, including nociception. It is known that H(2)S causes neurogenic inflammation and elicits hyperalgesia. Here we show that H(2)S activates mouse transient receptor potential ankyrin 1 (TRPA1) channels and elicits acute pain, using TRPA1-gene deficient mice (TRPA1(-/-)) and heterologous expression system. In wild-type mouse sensory neurons, H(2)S increased the intracellular Ca(2+) concentration ([Ca(2+)](i)), which was inhibited by ruthenium red (a nonselective TRP channel blocker) and HC-030031 (a TRPA1 blocker). H(2)S-responsive neurons highly corresponded to TRPA1 agonist-sensitive ones. [Ca(2+)](i) responses to H(2)S were observed in neurons from transient receptor potential vanilloid 1 (TRPV1(-/-)) mice but not from TRPA1(-/-) mice. Heterologously expressed mouse TRPA1, but not mouse TRPV1, was activated by H(2)S. H(2)S-induced [Ca(2+)](i) responses were inhibited by dithiothreitol, a reducing agent. Analyses of the TRPA1 mutant channel revealed that two cysteine residues located in the N-terminal internal domain were responsible for the activation by H(2)S. Intraplantar injection of H(2)S into the mouse hind paw caused acute pain which was significantly less in TRPA1(-/-) mice. The [Ca(2+)](i) responses to H(2)S in sensory neurons and in heterologously expressed channels, and pain-related behavior induced by H(2)S were enhanced under acidic conditions. These results suggest that H(2)S functions as a nociceptive messenger through the activation of TRPA1 channels. TRPA1 may be a therapeutic target for H(2)S-related algesic action, especially under inflammatory conditions.

Spin-density matrix elements for γp→K*0Σ+ at Eγ=1.85-3.0 GeV with evidence for the κ(800) meson exchange

The exclusive reaction γp→K(+)π(-)Σ(+) was measured for the first time using linearly polarized photons at beam energies from 1.85 to 2.96 GeV. Angular distributions in the rest frame of the K(+)π(-) system were fitted to extract spin-density matrix elements of the K(*0) decay. The measured parity spin asymmetry shows that natural-parity exchange is dominant in this reaction. This result clearly indicates the need for t-channel exchange of the κ(800) scalar meson.

JTT-130, a novel intestine-specific inhibitor of microsomal triglyceride transfer protein, ameliorates impaired glucose and lipid metabolism in Zucker diabetic fatty rats

AIM

Microsomal triglyceride transfer protein (MTP) takes part in the mobilization of triglyceride-rich lipoproteins from enterocytes and hepatocytes. We investigated the effects of JTT-130, a novel intestine-specific MTP inhibitor, on impaired glucose and lipid metabolism in Zucker diabetic fatty (ZDF) rats.

METHODS

Male ZDF rats were fed a regular powdered diet with or without JTT-130 as a food admixture (0.01-0.02%) for 6 weeks. Food intake, body weight, blood biochemical parameters, fecal lipid contents, hepatic lipid contents, tissue mRNA levels and glucose utilization in adipose tissues were assessed. An intraperitoneal glucose tolerance test (IPGTT) and histological analysis of the pancreas were performed.

RESULTS

JTT-130 treatment decreased food intake, glycated hemoglobin, plasma levels of glucose, triglycerides and total cholesterol, hepatic levels of triglycerides and cholesterol and hepatic mRNA levels of glucose-6-phosphatase, phosphoenolpyruvate carboxykinase and fructose-1,6-bisphosphatase. JTT-130 treatment increased fecal levels of free fatty acids and cholesterol, plasma levels of glucagon-like peptide-1 and peptide YY, mRNA levels of glucose transporter 4 (GLUT4) and lipoprotein lipase in adipose tissues and GLUT4 in muscle and glucose utilization in adipose tissues. Plasma insulin decreased after 2 weeks and increased after 4 weeks of JTT-130 treatment. Plasma glucose in the JTT-130-treated rats was lower with higher plasma insulin than in the control rats during the IPGTT. The islets of the JTT-130-treated rats were larger and contained more insulin than those of the control rats.

CONCLUSIONS

JTT-130 ameliorates impaired glucose and lipid metabolism in the ZDF rats thereby suggesting that JTT-130 could be useful for prevention and treatment of type 2 diabetes.

Deformable self-propelled domain in an excitable reaction-diffusion system in three dimensions

We derive a set of equations of motion for an isolated domain in an excitable reaction-diffusion system in three dimensions. In the singular limit where the interface is infinitesimally thin, the motion of the center of mass coupled with deformation is investigated near the drift bifurcation where a motionless domain becomes unstable and undergoes migration. This is an extension of our previous theory in two dimensions. We show that there are three basic motions of a domain, straight motion, rotating motion, and helical motion. The last one is a characteristic of three dimensions. The phase diagram of these three solutions is given in the parameter space of the original reaction-diffusion equations.

JTT-130, a novel intestine-specific inhibitor of microsomal triglyceride transfer protein, suppresses high fat diet-induced obesity and glucose intolerance in Sprague-Dawley rats

AIM

Microsomal triglyceride transfer protein (MTP) takes part in the mobilization and secretion of triglyceride-rich lipoproteins from enterocytes and hepatocytes. We investigated the effects of JTT-130, a novel intestine-specific MTP inhibitor, on high fat diet-induced obesity and glucose intolerance.

METHODS

Male Sprague-Dawley rats were fed a 3.1% fat diet or a 35% fat diet with or without JTT-130 as a food admixture (0.029%). Food intake, body weight, abdominal fat, hepatic triglyceride, faecal free fatty acids and plasma levels of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) were assessed. Plasma levels of glucose and insulin were measured during intraperitoneal glucose tolerance tests. In addition, indirect calorimetry was performed on rats fed with a 35% fat diet.

RESULTS

JTT-130 treatment decreased body weights, abdominal fat and hepatic triglyceride with suppression of food intake and elevation of faecal free fatty acids and plasma GLP-1 and PYY levels in rats fed with the 35% fat diet, whereas no significant effects on these parameters except for increased faecal free fatty acids were observed in rats fed with the 3.1% fat diet. JTT-130 treatment decreased plasma levels of glucose and insulin during intraperitoneal glucose tolerance tests on rats fed with the 35% fat diet, but not on rats fed with the 3.1% fat diet. JTT-130-treated rats showed increased O(2) consumption and CO(2) production on a 35% fat diet.

CONCLUSIONS

JTT-130 suppresses high fat diet-induced obesity and glucose intolerance with suppression of food intake and fat absorption and could be useful for prevention and treatment of obesity and obesity-related insulin resistance.

Transfection of human HGF plasmid DNA improves limb salvage in Buerger's disease patients with critical limb ischemia

AIM

Hepatocyte growth factor is a potent angiogenic agent. This study investigated the efficacy and safety of intramuscular injection of naked plasmid DNA encoding the human hepatocyte growth factor gene in Japanese patients with Buerger's disease and critical limb ischemia.

METHODS

An open-label clinical study was performed at eight hospitals in Japan from May 2004 to April 2008. Ten patients were enrolled. They had Buerger's disease with ischemic ulcers, were not candidates for revascularization, and were unresponsive to conventional drug therapy. Treatment consisted of 8 injections (total dose: 4 mg) of hepatocyte growth factor plasmid, which were administered into the calf muscles and/or distal thigh muscles of the ischemic limbs under ultrasound guidance. Administration was done twice at an interval of 4 weeks. If there was no improvement after 2 doses, a 3rd dose could be administered. The response to treatment was evaluated from the reduction of ischemic ulcer size.

RESULTS

The size of ischemic ulcers showed a decrease in 6/9 (66.7%) patients and the ulcers healed completely in 5/9 (55.6%) patients after gene therapy. Major amputation was not required. There were no deaths and no major safety concerns.

CONCLUSION

Hepatocyte growth factor gene therapy is safe and effective for critical limb ischemia in patients with Buerger's disease.

Adenosine and inosine release during hypoxia in the isolated spinal cord of neonatal rats

BACKGROUND AND PURPOSE

Adenosine and inosine accumulate extracellularly during hypoxia/ischaemia in the brain and may act as neuroprotectants. In spinal cord, there is pharmacological evidence for increases in extracellular adenosine during hypoxia, but no direct measurements of purine release. Furthermore, the efflux pathways and origin of extracellular purines are not defined. To characterize hypoxia-evoked purine accumulation, we examined the effect of acute hypoxia on the extracellular levels of adenosine and inosine in isolated spinal cords from rats.

EXPERIMENTAL APPROACH

Extracellular adenosine and inosine concentrations were assayed in an in vitro preparation of the isolated spinal cord of the neonatal rat by HPLC.

KEY RESULTS

The extracellular level of inosine was about 10-fold higher than that of adenosine. Acute hypoxia (10 min) caused a temperature-dependent increase in these two purines, which were inhibited by an increase in external Ca(2+), but not by several inhibitors of efflux pathways or metabolic enzymes of adenine nucleotides. Inhibitors of adenosine deaminase or the equilibrative nucleoside transporter (ENT) abolished the hypoxia-evoked increase in inosine but not adenosine. The inhibition of glial metabolism abolished the increase of both purines evoked by hypoxia but not by oxygen-glucose deprivation, hypercapnia or an adenosine kinase inhibitor.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that hypoxia releases adenosine itself from intracellular sources. Inosine formed intracellularly may be released through ENTs. During hypoxia, astrocytes appear to play a key role in purine release from neonatal rat spinal cord.

Down-regulation of ABCC11 protein (MRP8) in human breast cancer

AIM

To investigate the expression of ABCC11 (MRP8) protein in normal breast tissue, and examine the difference in ABCC11 mRNA and protein expression between normal breast and breast cancer tissues taking into account ABCC11 genotype (a functional SNP, rs17822931) and estrogen receptor (ER) status.

METHODS

Sections of paraffin-embedded normal and malignant tissues from 10 patients with invasive ductal carcinoma were used for immunohistochemical analysis. DNA and RNA were extracted from the same sections and used for genotyping and ABCC11 transcript expression measurement by quantitative RT-PCR.

RESULTS

A strong expression of ABCC11 was found in epithelial and myoepithelial cells of normal breast lobules and ducts in individuals with different ABCC11 genotypes. A predominant decrease of ABCC11 expression was observed in malignant tissue compared to normal beast specimen (8 of 10 cases), despite four out of ten tumors showed the elevated ABCC11 mRNA level as compared to the normal counterpart. Neither ABCC11 mRNA nor protein expression in normal or cancerous tissue correlated with ER status.

CONCLUSION

The expression of ABCC11 protein appears to be decreased in most BC. The effect of ABCC11 protein on breast cancer chemosensitivity is likely to be more complex than that which can be directly inferred from ABCC11 genotype and mRNA expression level in the tumor.

Learning of thoracoscopic radical esophagectomy: how can the learning curve be made short and flat?

Attainment of proficiency in video-assisted thoracoscopic radical esophagectomy (VATS) for thoracic esophageal cancer requires much experience. We have mastered this procedure safely under the direction of an experienced surgeon. After adoption of the procedure, the educated surgeon directed induction of this surgical procedure at another institution. We evaluated the efficacy of instruction during the induction period by comparing the results at the two institutions in which VATS had been newly induced. We defined the induction period as the time from the beginning of VATS to the time when the last instruction was carried out. From January 2003 to December 2007, 53 patients were candidates for VATS at Kanazawa University (institution 1). Of these, 46 patients underwent curative VATS by a single operator. We divided this period into three parts: the induction period of VATS, post-induction period, and proficient period when the educated surgeon of institution 1 directed the procedure at Maebashi Red Cross Hospital (institution 2). At institution 1, 12 VATS were scheduled, and nine procedures (75%) (group A) including eight instructions were completed during the induction period (from January 2003 to August 2004). Thereafter, VATS was performed without instruction. In the post-induction period, nine VATS were scheduled, and eight procedures (88.8%) (group B) were completed from September 2004 to August 2005. Subsequently, 32 VATS were scheduled, and 29 procedures (90.6%) (group C) were completed during the proficient period (from September 2005 to December 2007). The surgeon at Maebashi Red Cross Hospital (institution 2) started to perform VATS under the direction of the surgeon who had been educated at institution 1 from September 2005. VATS was completed in 13 (76.4%) (group D) of 17 cases by a single surgeon including seven instructions during the induction period at institution 2 from September 2005 to December 2007. No lethal complication occurred during the induction period at both institutions. We compared the results of VATS among four groups from the two institutions. There were no differences in the background and clinicopathological features among the four groups. The number of dissected lymph nodes and amount of thoracic blood loss were similar in the four groups (35 [22-52] vs 41 [26-53] vs 32 [17-69] vs 29 [17-42] nodes, P = 0.139, and 170 [90-380] vs 275 [130-550] vs 220 [10-660] vs 210 [75-543] g, P = 0.373, respectively). There was no difference in the duration of the thoracic procedure during the induction period at the two institutions. However, the duration of the procedure was significantly shorter in the proficient period of institution 1 (group C: 266 [195-555] minutes) than in the induction period of both institutions (group A: 350 [280-448] minutes [P = 0.005] and group D: 345 [270-420] mL [P = 0.002]). There were no surgery-related deaths in any of the groups. The incidence of postoperative complications did not differ among the four groups. Thoracoscopic radical esophagectomy can be mastered quickly and safely with a flat learning curve under the direction of an experienced surgeon. The educated surgeon can instruct surgeons at another institution on how to perform thoracoscopic esophagectomy. The operation time of thoracoscopic surgery is shortened by experience.

Randomized Clinical Trial of Treatment for TMJ Disc Displacement

Of the various conservative treatment modalities available for temporomandibular disorders, we believe that therapeutic exercise has a good prognosis, especially for anterior disc displacement without reduction. Since its effectiveness has not been extensively evaluated, we conducted a comparative study to verify the hypothesis that treatment efficacy would not differ for exercise and occlusal splints. Fifty-two individuals with anterior disc displacement without reduction were randomly assigned to a splint or a joint mobilization self-exercise treatment group. Four outcome variables were evaluated: (i) maximum mouth-opening range without and (ii) with pain, (iii) current maximum daily pain intensity, and (iv) limitation of daily functions. All outcome variables significantly improved after 8 weeks of treatment in both groups. In particular, the mouth opening range increased more in the exercise group than in the splint group. This result demonstrates that therapeutic exercise brings earlier recovery of jaw function compared with splints.

Linkage disequilibrium due to random genetic drift in finite subdivided populations

In order to clarify the mechanisms responsible for the observed linkage disequilibrium, such as that found between markers in the major histocompatibility complex of man and mouse, linkage disequilibrium between two linked loci was studied for a finite population with a subdivided structure. The infinite allele model was used. In analogy with the subdivision of the inbreeding coefficient, the linkage disequilibrium coefficient was subdivided, and various variance components of disequilibrium were defined. It was found that the disequilibrium components may get very large when migration is limited if the correlation of alleles at the two loci within a colony is taken relative to that of the entire population. In other words, with limited migration, random genetic drift of gamete types prevails in each colony. A possible test in which the variance components of disequilibrium are compared is suggested; the test discriminates between epistatic natural selection and limited migration, showing the former as the main cause of the observed linkage disequilibrium. It is pointed out that the major histocompatibility complex polymorphism is in accord with the population genetics model of multigene families that incorporate gene conversion or double unequal crossing-over between the loci in the supergene family.

Sequence variability of immunoglobulins considered from the standpoint of population genetics

The probability of gene identity between members of a multigene family was investigated, assuming mutation, random genetic drift, and unequal crossing-over. The theoretical results on the equilibrium and transient behavior of the identity probability were applied to the analyses of sequence variability in the variable regions of immunoglobulins. The probability of amino acid identity between corresponding residue sites at different but homologous immunoglobulin sequences was computed both within and between species from data reported by other workers. The average probability of amino acid identity was obtained for the hypervariable regions and also for the framework regions. From statistical analyses based on population genetics theory it is concluded that somatic mutations cannot be the major cause of hypervariability and that the results can readily be explained by the germ line theory.

Evaluation of the distribution and orientation of remineralized enamel crystallites in subsurface lesions by X-ray diffraction

Remineralization is the process by which hydroxyapatite (HAp) is restored in enamel subsurface lesions, and transversal microradiography (TMR) has been used to analyze remineralization in terms of the recovery of mineral content. In this study, we directly detected the distribution and orientation of longitudinal HAp crystallite at the remineralized zone in enamel subsurface lesions by using an X-ray microbeam (6-mum diameter) diffraction method. This method was demonstrated and involves the simultaneous detection of wide-angle X-ray diffraction (WAXRD) and small-angle X-ray scattering (SAXS). WAXRD reflects the amount of HAp crystallites, and SAXS reflects that of voids in crystallites. The polished surface of a bovine enamel block was divided into three zones of sound, demineralized, and remineralized zones. Thin sections of approximately 150 mum thickness were then cut perpendicular to the surface, and subjected to WAXRD and SAXS following TMR. The increase in the amount of HAp crystallites and the decrease in voids in the crystallites at the remineralized zone were detected by WAXRD and SAXS, respectively, which was consistent with the result of TMR. This study indicates that both the spatial distribution and orientation of the restored HAp crystals in the remineralization process at the subsurface lesion can be simultaneously analyzed by the X-ray diffraction methods.

Conservative treatment for patients with intermittent claudication

AIM

The effect of pharmacotherapy or supervised exercise training on patients with intermittent claudication was assessed.

METHODS

One hundred patients with stable intermittent claudication due to arteriosclerosis obliterans were analyzed. We divided the patients into 2 groups: patients treated by pharmacotherapy alone (Group A: 39 claudicants) and patients treated by supervised exercise training and pharmacotherapy (Group B: 61 claudicants). The changes in ankle-brachial pressure index (ABI) and recovery time of ABI after a 40-m walk (RT(40)) and absolute claudication distance (ACD) on a treadmill before and after each treatment were assessed.

RESULTS

In Group A, RT(40) decreased from 9.5 +/- 5.8 min at the baseline to 6.4 +/- 3.5 min after 6 months (P=0.0002). In Group B, it decreased from 9.7+/-5.2 min at the baseline to 6.3+/-4.2 min after 3 weeks (P<0.0001). In Group A, ACD increased from 249+/-177 m at the baseline to 317+/-168 m after 6 months (P=0.0003). In Group B, it increased from 143+/-90 m at the baseline to 257+/-161 m after 3 weeks (P<0.0001).

CONCLUSION

Hemodynamics and walking ability were improved by either short-term supervised exercise training or midterm pharmacotherapy. RT(40) may be useful for predicting the effect of conservative treatment on intermittent claudication. Greater increases in ACD after treatment can be achieved in claudicants with a shorter RT(40) before conservative treatment.

Three-year cardiovascular events and disease progress in patients with peripheral arterial disease: results from the Japan Medication Therapy for Peripheral Arterial Disease (J-METHOD)

AIM

To investigate the current status of peripheral arterial disease (PAD) drug treatment in Japan, and the effects of drug treatment, risk factors, and complications on disease progress and onset of cardiovascular events in PAD patients.

METHODS

In this prospective observational cohort study, 557 PAD patients were followed up for 3 years, and the current status of PAD treatment, risk factors, and cardiovascular events were monitored.

RESULTS

Three drugs, i.e., beraprost sodium, cilostazol, and aspirin, were most frequently used. The patients who had undergone vascular reconstruction of the lower limbs before enrollment showed significant improvement in ABI. Among the patients who had not undergone vascular reconstruction before enrollment, there was a significant improvement in ABI after treatment with beraprost. During the observation period, cardiovascular deaths occurred in 35 patients (6.3%), heart diseases in 63 (11.3%), brain diseases in 39 (7.0%), and events in the lower limbs in 94 (16.9%). The factors affecting the increase of the cardiovascular events were explored by multivariate analysis (Cox regression analysis). As a result, age (75 years or older), ischemic heart disease and increase in severity on the Fontaine classification were identified as significant factors for cardiovascular deaths, whereas kidney disorders and increase in severity on the Fontaine classification were identified for heart diseases, the number of oral drugs for treating PAD was identified for brain diseases, and age (younger than 75 years), dialysis, ABI (less than 0.7) and aspirin were identified for the events in the lower limbs.

CONCLUSION

As a result of the three-year follow-up on the Japanese PAD cohort, the current status of PAD treatment, risk factors, and cardiovascular events could be identified.